Computerized numerical control method

ABSTRACT

A CNC method controls a plurality of paths with a single computerized numerical control apparatus. In the CNC method, an order (6) in which to execute part programs (5) for the respective paths (4) is designated, and the part programs (5) are sequentially executed in the designated order. The contents of the part programs (5) can thus be checked for each of the part programs.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a computerized numerical control (CNC)method of controlling a plurality of paths with a single computerizednumerical control apparatus, and more particularly to a CNC method ofsequentially executing part programs for respective paths.

2. Description of the Related Art

There has recently been used a multipath control method which controls aplurality of paths with a single computerized numerical control (CNC)apparatus in order that the CNC apparatus can operate with morefunctions and a workpiece can be machined in a shorter period of time.

In computerized numerical control apparatus controlled by the multipathcontrol method, part programs for respective paths are generallyexecuted simultaneously, i.e., parallel to each other.

It is however difficult or even practically impossible to check the partprograms which are executed parallel to each other.

SUMMARY OF THE INVENTION

In view of the aforesaid problems of the conventional CNC method, it isan object of the present invention to provide a CNC method which cansequentially execute part programs for respective paths.

To achieve the above object, there is provided in accordance with thepresent invention a CNC method of controlling a plurality of paths witha single computerized numerical control apparatus, the method comprisingthe steps of designating an order in which to execute part programs forthe respective paths, and sequentially executing the part programs forthe respective paths in the designated order.

The part programs for the respective paths are designated in a certainorder in which they are to be executed. The part programs are thenexecuted in the designated order, and contents thereof are checked foreach of the part programs.

If necessary an actual order may be modified.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view showing a display screen used in a CNC method accordingto the present invention;

FIG. 2 is a flowchart of a sequence of the CNC method of the presentinvention; and

FIG. 3 is a block diagram of the hardware of a computerized numericalcontrol apparatus for multipath control according to the presentinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

An embodiment of the present invention will hereinafter be describedwith reference to the drawings.

FIG. 1 shows a display screen used in a CNC method according to thepresent invention. A CRT/MDI unit has a display screen 1 which includesa multipath setting display area 2, and a selection display area 3 forselecting a parallel execution mode or a sequential execution mode. InFIG. 1, a parallel execution mode is selected, and the selection of theparallel execution mode is indicated by an underline which is displayed.

In a normal machining process, part programs for respective paths areexecuted simultaneously parallel to each other to machine a plurality ofworkpieces at the same time. At times, one workpiece may be machinedsimultaneously by a number of machining heads and corresponding partprograms. If the part programs were executed as they are, the partprograms would be simultaneously executed, and any checking of thesepart programs would be practically impossible to carry out.

According to the present invention, a selection capability is providedwhich allows the part programs for respective paths to be sequentiallyexecuted. The selection capability displays a path number section 4 fordisplaying path numbers, a program number section 5 for displaying thepart programs for the paths, such as Oaaaa, Obbbb, Occcc, and so on, anda sequence number section 6 for setting an order in which to execute thepart programs.

In the selection display area 3, a sequential execution mode isselected, and an order in which to execute the part programs is presetin the sequence number section 6. According to the preset order, acomputerized numerical control apparatus does not execute the partprograms parallel to each other, but executes the part programs in theorder set in the sequence execution section 6. As a result, theprogrammer can confirm the contents of the part programs while they arebeing executed one by one. Furthermore, the programmer can correcterrors in the part programs, if necessary, and can also vary theparallel execution order or the like.

FIG. 2 shows a sequence of the CNC method according to the presentinvention. The numerals following a letter "S" in FIG. 2 indicate stepnumbers.

[S1]A sequential execution mode is selected and an order in which toexecute the part programs for the paths is preset on the multipathsetting display screen.

[S2]When a cycle start button is pushed, the part programs for therespective paths are executed in the preset order.

[S3]Whether the contents, steps, and order of machining processes arecorrect or not is checked.

[S4]If there is an error, the contents of the part programs arecorrected, and the order in which the part programs are executedparallel to each other is varied.

In this manner, the contents of the part programs for the respectivepaths can be corrected, and the order in which the part programs are tobe executed parallel to each other can be varied so as to be optimum.

FIG. 3 shows in block form the hardware of the computerized numericalcontrol apparatus for multipath control according to the presentinvention. Designated at 11 is a channel bus which comprises amultimaster bus which can connect channels. The channel bus 11 has anumber of slots 11a, 11b, . . . 11g to which channels and other units(described later) can be connected.

The CRT/MDI unit, denoted at 12, displays the multipath setting displayscreen, and enters an order in which to execute the part programs forthe respective paths, through a keyboard. The reference numerals 13, 14indicate axis control modules each capable of controlling servomotorsfor 2 or 3 axes. An I/0 circuit 15 receives input signals from andtransmits output signals to an external circuit. A PC (programmablecontroller) is omitted from illustration in FIG. 3.

Denoted at 21, 22, 23 are channels, each having the function of onecomputerized numerical control apparatus. Therefore, one channel canread, decode, and execute numerical control commands, and can alsocontrol devices such as the CRT/MDI unit. Consequently, each of thechannels can execute commands for a certain number of axes, which haveheretofore been executed by a conventional computerized numericalcontrol apparatus.

On a two-head numerical control engine lathe, for example, a firstspindle, an Xl axis, and a Z1 axis are controlled by the channel I 21, asecond spindle, an X2 axis, and a Z2 axis are controlled by the channelII 22, and the channel III 23 is used as a master channel forcontrolling overall operation such as supervising of the other channels.The channel I 21 controls the CRT/MDI unit 12 through the channel bus11.

These channels 21 through 23 are coupled to the channel bus 11 and sharethe executing operation. If the executing capacity of one of thechannels runs low, part of the operation to be executed is transferredto the other channels. For example, while the channel I 21 is executinginterpolation at very small intervals, and the channel II 22 isexecuting linear interpolation, then part of calculations in advance ofthe interpolation to be executed by the channel I 21 can be executed bythe channel II 22. As a result, the executing capacities of thesechannels can be balanced so that no unbalanced execution by thesechannels will take place.

The channel III 23 operates as a master channel to execute overallcontrol processes such as the regulation of priority to use the channelbus 11 and the supervision of the other channels. Of course, the channelIII 23 can also control the spindles and the axes. If the channel III 23is given so many tasks that it can no longer effect the overall controlprocesses and also if the other channels have a sufficient executingcapacity, then it is possible to transfer the master right to the otherchannels.

With the present invention, as described above, since the part programsfor the respective paths are sequentially executed in the designatedorder, they can successively be checked to determine whether they areproperly prepared.

The present invention is also effective to determine whether the orderin which to execute the paths is optimum or not.

What is claimed is:
 1. A CNC method of controlling a plurality of pathsmachined by a multi-head numerical control engine lathe, using a singlecomputerized numerical control apparatus, said method comprising thesteps of:(a) storing a plurality of part programs, corresponding to theplurality of paths, for parallel execution by the single computerizednumerical control apparatus; (b) designating on a display screen anorder in which to execute the path programs for respective paths; (c)sequentially executing the part programs for the respective paths in theorder designated in step (b); (d) checking the part programs independence upon said executing in step (c); (e) correcting any errors inthe part programs detected during said checking in step (d); and (f)machining a workpiece by parallel execution of the part programs afterperforming steps (a)-(e).
 2. A CNC method according to claim 1, whereinthe multi-head numerical control engine lathe is a two-head numericalcontrol engine lathe.